在 Ubuntu 上安裝 Jenkins 告訴我“包 ‘jenkins’ 沒有安裝候選者”

我需要在 Ubuntu 20.4.1 上安裝 Jenkins。

我已經完成了以下工作：

• apt-get -y install openjdk-8-jdk（它是 Java 14.0.1）
• wget -q -O - http://pkg.jenkins-ci.org/debian-stable/jenkins-ci.org.key | apt-key add -（響應“OK”）
• sudo sh -c 'echo deb https://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'（文件存在並且其中有這一行）
• sudo apt update, 回复:

Hit:1 http://de.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://de.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://de.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:4 http://de.archive.ubuntu.com/ubuntu focal-security InRelease
Ign:5 https://pkg.jenkins.io/debian-stable binary/ InRelease
Get:6 https://pkg.jenkins.io/debian-stable binary/ Release [2,044 B]
Get:7 https://pkg.jenkins.io/debian-stable binary/ Release.gpg [833 B]
Ign:7 https://pkg.jenkins.io/debian-stable binary/ Release.gpg
Reading package lists... Done
W: GPG error: https://pkg.jenkins.io/debian-stable binary/ Release: The following signatures couldn't 
be verified because the public key is not available: NO_PUBKEY FCEF32E745F2C3D5
E: The repository 'http://pkg.jenkins.io/debian-stable binary/ Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.      
N: See apt-secure(8) manpage for repository creation and user configuration details.

• sudo apt install jenkins, 回复:

root@ubuntu-server:~# sudo apt install jenkins
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package jenkins is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'jenkins' has no installation candidate

我該怎麼做才能apt找到 Jenkins 包以便安裝它？

您正在遵循非官方或過時的說明。

因此，您導入了錯誤的 GPG 密鑰。Jenkins 於 2020 年 4 月 16 日更改了他們的 GPG 密鑰。您需要按照目前官方指示導入正確的密鑰。

wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -

要在 Ubuntu 上安裝 Jenkins，請遵循以下命令集：

wget -q -O - https://pkg.jenkins.io/debian-stable/jenkins.io.key | 
 sudo apt-key add -
sudo sh -c 'echo deb https://pkg.jenkins.io/debian-stable binary/ > \
/etc/apt/sources.list.d/jenkins.list'
sudo apt-get update
sudo apt-get install jenkins

引用自：https://serverfault.com/questions/1034893